package com.zhiyu.interceptor;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.zhiyu.common.JWTToken;
import com.zhiyu.entity.VO.ResponseVO;
import com.zhiyu.util.JWTUtil;
import com.zhiyu.util.JsonConvertUtil;
import com.zhiyu.util.ResponseUtil;
import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletOutputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Component
public class JWTFilter extends BasicHttpAuthenticationFilter {

    @Autowired
    private ResponseUtil responseUtil;

    @Autowired
    private JWTUtil jwtUtil;

    @Override
    protected boolean isLoginAttempt(ServletRequest request, ServletResponse response) {
        String token = getToken(request);
        return !StringUtils.isEmpty(token);
    }

    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) throws AuthenticationException {
        String token = getToken(request);

        //将token封装成AuthenticationToken交给realm验证
        JWTToken jwtToken = new JWTToken(token);

        getSubject(request, response).login(jwtToken);

        //没有抛出异常代表通过验证
        return true;
    }

    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
        if (isLoginAttempt(request, response)) {
            try {
                executeLogin(request, response);
            } catch (AuthenticationException e) {
                return false;
            }
        }

        return true;
    }

    @Override
    protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {
        try {
            ServletOutputStream outputStream = response.getOutputStream();
            ResponseVO responseVO = responseUtil.tokenInvalid();
            String data = JsonConvertUtil.objectToJson(responseVO);

            outputStream.write(data.getBytes());
            outputStream.flush();
            outputStream.close();
        } catch(IOException e) {
        }

        return super.onAccessDenied(request, response);
    }

    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest)request;
        HttpServletResponse httpServletResponse = (HttpServletResponse)response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));

        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }

        return super.preHandle(request, response);
    }

    private String getToken(ServletRequest request) {
        return ((HttpServletRequest) request).getHeader(jwtUtil.getHeader());
    }
}
